Two-package coating system comprising a polyester having an acid number of at least 50 in one of the packages thereof



essary characteristics.

esters, and particularly epoxidized fatty oils.

United States Patent 3 218 274 TWO-PACKAGE coArrNd SYSTEM COMPRISING APOLYESTER HAVING AN ACID NUMBER OF AT LEAST 50 IN ONE OF THE PACKAGESTHEREOF Robert vA. Boller, Rich'field, and Richard B. Graver,

Minneapolis, Minn., assignors to Archer-Daniels-Midland Company,Minneapolis, Minn., a corporation of Delaware No Drawing. Filed Feb. 13,1961, Ser. No. 88,613

18 Claims. (Cl. 26022) This invention relates to new coatings vehiclecompositions which form hard, and improved coatings. These new coatingsvehicles are comprised of the reaction products of non-drying epoxidizedfatty ester materials, such .as epoxidized fatty oils or epoxidizedfatty glycerides,

epoxidized synthetic esters of long chain fatty acids and epoxidizedfatty alcohols, with partial esters of polyols and polycarboxylic acidor anhydride materials. More particularly, this is an improvement in themethod of formulating economical coatings vehicles using solventmixtures of epoxidized long chain fatty ester systems having internaloxirane groups and partial esters of modified or unmodified phthalicacid or anhydride materials with polyhydroxy compounds, and the productsderived therefrom.

Heretofore, epoxidized long chain monomeric and polymeric fatty esters,such as fatty oils and the like, have served more beneficially in anon-hardening relationship, as plasticizing agents in resinouscompositions. Otherwise the formation of hard films or plastics withepoxidized oils has been through use of strong polycarboxylic acids,including certain adducts of such acids or anhydrides which have a lowpH value on other defined nec- However, with these materials it has beenfound that there are a number of problems present in attempting toutilize such acids and anhydride materials at high solids levels withconventional solvents. This is particularly true with the low costphthalic acid and phthalic anhydride when used with the epoxidized fattyester compounds, as epoxidized fatty oils or fatty glycerides, and theepoxidized esters of fatty acids. Some of these problems are:

(1) Low solubility is obtained in conventional paint and varnishsolvents.

(2) Low solids are required.

(3)'Viscosity control is difficult.

(4) Raw material cost is uneconomical.

(5) Versatility in formulating varnishes and paints is limited.

(6) Seeding in the films is difficult to prevent.

By comparison it has now been particularly discovered that the lowercost phthalic acid and phthalic anhydride can be more practically,economically and effectively utilized to form coatings vehicles incombination with economical paint and varnish solvents and epoxidizedfatty This is accomplished by first forming esterification products ofthe particular polycarboxylic acid materials and polyhydroxyl alcoholswith a retained acid value of 50 or more as described herein.Conventional paint and varnish solvent coating systems of epoxidizedesters of fatty acids can now be used with phthalic acid materials moreeffectively and in a more economically'feasible manner to form pigmentedand unpigmented hard, mar resistant, durable films. Further, thephthalic acid material may be modified with additional polyester forforming improved hard Accordingly, it is an object of this invention toprovide improved, hard, mar-resistant, durable coatings from solventsolutions of normally non-drying epoxidized fatty ester materials andpartial esters of phthalic acid mate- 3,218,274 Patented Nov. 16, 1965rials having controlled viscosity in conventional paint and varnishsolvents.

Another object is to form and provide clear and pigmented dry films fromepoxidized fatty oils and modified anhydrides which have outstandinghardness, durability, color retention and mar resistance.

An additional object of this invention is to provide improved hardcoating films of epoxidized fatty ester and partial ester materials;including the processof preparing pigmented and non-pigmented coatingvehicle compositions for making such films comprising mixing non-dryingepoxidized oils, epoxidized glycerides, epoxidized esters of long chainfatty acids, and/or epoxidized fatty alcohols, and mixtures thereof incombination with partial esters of phthalic acid or phthalic anhydridematerials and polyfunctional alcohols having aretained acid value of atleast 50 in a paint, varnish or enamel solvent, as indicated.

Another object of this invention is to provide economically proficientair drying and baking paint vehicles of epoxidized fatty esters, aspolyepoxidized fatty oils and polyepoxidized esters of long chain fattyacids, in combination with partial esters of esterificationpolymers .ofphthalic acid material and polyhydroxy alcohol. This combination formsclear and pigmented, hard, tough, mar resistant coatings with excellentadhesion, flexibility, chemical resistance, durability and colorretention To the accomplishment of the foregoing and related ends, thisinvention then comprises the features above and hereinafter set forth,as more fully described and particularly pointed out by certainillustrative embodiments. These are indicative of the ways in whichimproved coatings vehicles can be made from non-drying epoxidized estersof long chain fatty compounds in combination with partial estercondensation polymers of polycarboxylic acids, and particularlypolycarboxylic acid anhydrides and polyols, and the manner in whichhard, dur'able,'water and chemical resistant, flexible films areobtained.

The epoxidized esters of fatty acid compounds employed in this inventionare those of monomeric form having preferably 12 to 22 carbon atoms withinternal oxirane groups in the fatty chain portions and 1 through 10carbon atoms in the mono and polyhydric alcohol portions with or withoutinternal oxirane groups in the alcohol chain portions. The methods ofepoxidation of such compounds are well known to the art. Illustrativethereof are some preferred types of monomeric epoxy fatty estercompounds as epoxidized linseed oil, epoxidized soybean oil, epoxidizedsafiiower oil and the like having an iodine value of over beforeepoxidation and an oxirane value of at least 6% after epoxidation. Also,inclusive of the fatty esters, there may be utilized the many other longchain epoxidized fatty oils, fatty alcohols and mono or polyhydroxyester derivatives of ,vegetable oil, animal oil, marine oil and similarepoxidized synethetic compounds having modified or unmodified fatty oraliphatic and cycloaliphatic chains of 12 to 26 carbon atoms in the basechains. Such base chains also preferably have from 1 through 10 carbonatoms in substituent chain portions and the preferred hard film formingcompounds contain at least about 6% to 10% and more internal oxiranevalue. In addition, the mono and polyalcohol ester derivative of thefatty chains may or may not contain one or more oxirane groups, in theester portion. The preferred fatty ester oxirane compounds are thosedescribed and prepared in the manner shown in Wahlroos Patent No.2,813,878, Niederhauser Patent No. 2,485,160 and 2,543,419, Phillips etal. No. 2,779,771, Dazzi 2,745,846, Swern et al. 2,457,329 and the like.

Additional expoxidized fatty .ester compounds having a minimum of about3% oxirane value may be indicated as epoxy 2-ethyl hexyl tallate, epoxy1-5 pentane diol dioleate, epoxy hexanetriol dioleate mono acetate, andthe like. Other compounds with 1 to or more carbon atoms in the alcoholportion are epoxidized mono and polyhydroxy alcohol esters of fatty acidchains, including the epoxidized fatty alcohols, as9,10-epoxy-octadecanol, methyl oleate, oleyl alcohol,9,IO-dihydroxyoctadecanol and the like. These may have non-interferingsubstituents as halogen or other groups, as may be illustrated byepoxidized chlorohydroxyoctadecanol and the like containing an internaloxirane group or groups. Obviously, it will be recognized that there aremany epoxidized fatty oil and related like aliphatic and cycloaliphaticepoxidized compounds and epoxidized derivatives which are available.Essentially the typical fatty oils and fatty esters are indicated.However, many more can be illustrated and named, for example, epoxidizedtrilinoleate, trioleate, mono-oleate, monolinoleate, monolinolenate,monostearate dilinoleate, dilinoleate mono-oleate and many other wellknown glycerol esters. Also included are the substituted andunsubstituted epoxidized monoand polyhydric alcohol re-esterified andderivative products, including ethylene glycol, diethylene glycol, mono,di, and polypentaerythritol, sorbitol, and the like. Essentially, itwill be recognized that epoxidized products derived from dimerized andtrimerized fatty acids and fatty esters, including the epoxidized fattynitriles, amides and amine derivatives of the fatty chain compounds asherein described. Such compounds also include, for example, fattyesters, as mono-, di-, and polypentaerythritol esters of soy, tall,linseed, and the like, derived from fatty oils, fatty acids and similaraliphatic and cycloaliphatic compounds of analogous structure. Othersuch derivatives may include epoxidized oleyl phosphate, dioleylphosphate, oleyl chloride, octadeca dienyl chloride, oleyl mercaptan,and mixtures thereof and the like to form similar or addition reactionproducts, to these herein described.

It will be understood that the present film coating compositions, asherein described, are prepared and normally utilized as two packagesystems in the field of vehicle coating systems. It has not been foundpossible .to neutralize the partial esters in the presence of theepoxidized compounds and obtain systems which cure at ordinary room.temperature. Many neutralizing agents such as amines and the like formsalts with the described partial esters which are usually insoluble inthe epoxidized esters of fatty acid material and the conventionalaromatic paint and varnish solvents. The preferred solvents are of thearomatic type as xylol or toluol, used alone or in combinatioin withesters of ketones and/ or other con- .ventional enamel, paint andvarnish solvents having boiling points between about 100186 C. and drypoints about 110209 C. Such solvents are well known to the coating art.As indicated, the use of the epoxidized fatty esters described with thepartial esters of resinous polycarboxylic acid material, hereinafterdescribed, require a two package system for subsequent combination, byblending just before application and use. The use of two componentsystems has found increasing application since unusual film propertiescan be obtained which are superior to those obtainable from one packagesystems.

In general, the partial esters are esterification polymers which can berepresented by the reaction and resultant empirical formulas, asfollows:

where n is an integer of at least 2 and preferably greater than 2,usually 3 or 4 but may be greater. R and R are general symbols for thealkyl, aromatic, carbon or other organicstructures usually present inpolyhydroxy alcohols and polycarboxylic acids, respectively.

In this case R represents the balance of the polyhydroxy compound and Rrepresents the balance of the polycarboxylic anhydrides. Use of apolycarboxylic acid in place of the polycarboxylic anhydride may berepresented thus:

Of course the final product in this latter case may not be as simple asrepresented above. It is recognized that the second reaction may yieldpolymers and free acid. But the type of molecule represented above willbe the predominate species.

As indicated, the preferred partial ester of polycarboxylic acidmaterial is a polyhydroxymodified phthalic acid material. This mayinclude, in part, the more expensive hexachl-oroendomethylenetetrahydrophthalic acid or anhydride materials in admixture with thephthalic acid or phthalic acid anhydride, all of which are reacted witha polyhydroxy alcohol forming a mixture of partial esters, as hereindescribed and illustrated. Other examples of less preferredpolycarboxylic acid material portions for forming modifying partialesters are maleic acid or anhydride, tri-mellitic acid or anhydride,tetrachlorophthalic acid or anhydride, monochlorophthalic acid oranhydride, tetrahydrophthalic acid or anhydride, hexahydrophthalic acidor anhydride, and mixtures of the same, and the like, for modifyingreactivity. For some purposes, if it is desirable, suitable of thesematerials may be utilized alone, or in mixed form, for preparation ofpartial esters, which may then be mixed with the preferred partialesters.

The polyfunctional alcohols, for example, can be ethylene glycol,propylene glycol, glycerol, trimethylolethane, trimethylopropane,sorbitol and preferably pentaerythritol, dipentaerythritol,tripentaerythritol, or mixtures of the same, and the like. These areexemplary of the saturated alcohols used herein.

The following examples are exemplary and illustrate some preferred filmforming partial esters and some less preferred partial esters orcondensation esterification polymers for forming coating materials. Inthe overall, these are different chemicals prepared from relativeinitial ratios of a minimum of about 1.0 carboxyl to 1 hydroxyl to 3.0carboxyl to 1 hydroxyl and preferably about 1.8 carboxyl to 1 hydroxyl,and reacted to use preferably all the hydroxyl groups with retention ofan acid value of at least 50 in the said vehicle package portion, andforming the improved coating material herein provided.

EXAMPLE I This represents a partial ester of phthalic anhydride andpentaerythritol.

To a reaction flask equipped with a stirrer, thermometer and condenserwas charged 375 parts phthalic anhydride, parts of pentaerythritol and30 parts xylol by weight. The mixture was heated to 300320 F. and heldfor about 30 minutes. After cooling to 250 F., 160 parts n-butanol andparts xylol were added. The partial ester obtained had a viscosity of7.3 stokes, an acid value of about 287, a color of 1 on theGardner-Holdt scale and was 60 percent solids.

EXAMPLE II This represents a mixed partial ester of phthalic anhydride,maleic anhydride and pentaerythritol.

250 parts phthalic anhydride, 83 parts maleic anhydride, 120 partspentaerythritol and 30 parts xylol werecharged and reacted as in ExampleI. The product was reduced to 60% solids with 115 parts xyltol and partsbutanol. The viscosity was 11.2 stokes, and, the acid value was 312.

EXAMPLE III This represents a mixed partial ester with a functionalityof two.

148 parts of phthalic anhydride, 386 parts hexachloroendomethylenetetrahydrophthalic acid anhydride, 160 parts pentaerythritol and 20parts xylol were charged to a reactor equipped with a stirrer,thermometer, condenser and water trap for removing water ofesterification. The above mixture was esterified at 300-3 F. to an acidvalue of 160 at which time 18 parts of water had been distilled off. Thereaction product was cooled and thinned with 100 parts butanol and 240parts xylol. The final product was at 65% solids and had a viscosity of49.3 stokes.

EXAMPLE IV This represents a mixed partial ester with a functionality ofabout 4.

148 parts of phthalic anhydride, 386 parts hexachloroendomethylenetetrahydrophthalic acid anhydride, 80 parts pentaerythritol and 20 partsof xylol were charged and reacted as in Example III to an acid value ofabout 170. The product wa thinned to 70% solids with 80 parts butanoland 180 parts xylol. The viscosity was 74.4 stokes.

EXAMPLE V This represents a partial ester of hexachloroendomethylenetetrahydrophthalic acid and pentaerythritol with a functionality ofabout 4.

482.5 parts of hexachloroendomethylene tetrahydrophthalic acid, 50 partsof pent-aerythritol and 200 parts of xylol were reacted as in ExampleIII to an acid value of 100 and thinned to 60% solids with 52.5 partsxylol and 67.5 parts of the acetate of the monoethyl ether of ethyleneglycol (Cellosolve Acetate). The viscosity was 3.3 stokes.

EXAMPLE VI This represents a partial ester with a functionality of about4.

222 parts of phthalic anhydride, 193 parts of hexachloroendomethylenetetrahydrophthalic acid, 80 parts pentaerythritol and 208 parts xylolwere charged and reacted as in Example III to an acid value of about 160and thinned to 60% NV with 54 parts xylol and 66 parts of the acetate ofmonoethyl ether of ethylene glycol. The viscosity was 37.4 stokes.

EXAMPLE VII This represents a mixed partial ester of tetrahydrophthalicanhydride, hexachloroendomethylene tetrahydrophthalic acid, andpentaerythritol. 152 parts tetrahydrophthalic anhydride, 389 partschlorendic acid, 80 parts pentaerythritol and 216 parts xylol werereacted as in Example III to an acid value of about 170 and thinned to65% NV with 5-1 parts xylol and 66 parts of the acetate of monoethylether of ethylene glycol. The viscosity was 110 stokes.

EXAMPLE IX This represents a mixed partial ester of hexahydrophthalicanhydride, hexachloroendomethylene tetrahydrophthalic acid andpentaerythritol. 154 parts hexahydrophthalic anhydride, 389 partshexachloroendomethylene 6 tetrahydrophthalic acid, parts pentaerythritoland 217 parts xylol were reacted as in Example III to an AV of about 170and thinned to 65% NV with 53 parts xylol and 67 parts of the acetate ofmonoethyl ether ofethylene glycol. The viscosity was 217 stokes.

EXAMPLE X This represents a mixed partial ester of phthalic anhydride,hexachloroendomethylene tetrahydrophthalic acid, trimethylolpropane andpentaerythritol. 148 parts phthalic anhydride, 389 partshexachloroendomethylene tetrahydrophthalic acid, 31.5 partspentaerythritol, 56.4 parts trimethylolpropane and 151.7 parts xylolwere reacted as in Example III to an acid value of about 160 and thinnedto 60% NV with 172.1 parts xylol and 81 parts of the acetate ofmonoethyl ether of ethylene glycol. The viscosity was 5 stokes.

The preferred epoxidized compounds are primarily epoxidized fatty oilsor glycerides, including their substituted mono and polyhydroxy alcoholderivatives which are fundamentally esters of fatty acids havinginternal oxirane groups in the fatty chain portions. The following areillustrative of the normally non-drying fatty esters.

EXAMPLE XI Epoxidized soybean oil such as that sold under the trade nameof Admex 710 with an oxirane oxygen content of about 6.3%, a color of 1,a viscosity of about 5 stokes, and an iodine value of less than 5. Otherepoxidized soybean oils sold commercially and containing varyingpercentages of oxirane oxygen up to about 7% and iodine values as low asabout 1 can be used.

EXAMPLE XII Epoxidized safiiower oil containing about 7.4% oxiraneoxygen and prepared by the epoxidation of safflower oil usingepoxidation techniques well known to the art.

EXAMPLE XIII Epoxidized linseed oil containing about 9.0% oxirane oxygenand prepared by the epoxidation of linseed oil using epoxidationtechniques well known to the art.

EXAMPLE XIV Epoxidized 2-ethyl hexyl tallate. This material had thefollowing characteristics: Acid Value-0.2, Gardner Colorl, Viscosity0.5stokes, Specific Gravity-0.923, Oxirane oxygen content4.4%.

EXAMPLE XV Epoxidized 1-5 pentane diol dioleate. This material had thefollowing characteristics: Acid Value0.2, Gardner Colorl, Viscosity-4.1stokes, Specific Gravity 0.945, Oxirane oxygen content-4.1%.

EXAMPLE XVI Epoxidized hexanetriol dioleate mono acetate. This materialhad the following characteristics: Acid Value 0.2, Gardner Color-4,Viscosity-2.3 stokes, Specific Gravity-0.970, Oxirane oxygencontent3.7%.

Mixtures of the herein described epoxidized compounds, with thedescribed partial esters are in the ratio of 50-150 parts partial esterper parts epoxidized fatty ester and their application may be as clearvarnish or pigmented vehicles, in the manner hereinafter described. Theepoxy system reacts with the partial esters or resinous polycarboxylicacid materials, as follows:

R and R refer to the balance of the epoxidized material 7 and may or maynot include non-interfering aromatic, alkyl, and ester substituents withor without oxirane groups, depending upon the epoxides and partial estermaterial.

This representation illustrates how each reaction between a freecarboxyl group and an oxirane group produces a new hydroxyl group, a newester linkage and reduces the number of free carboxyl groups.

The'preferred use is as pigmented coating vehicles. Any non-reactiveinert pigment may be used by dispersing the pigment in either the epoxyportion or the partial ester portion-in a conventional manner. However,it is preferred to disperse the pigment in the epoxy portion, prior toits mixture with the partial ester portion, since the epoxy portion hassuperior pigment wetting properties.

V The following examples are representative of enamels prepared from theabove components, as follows:

1 (A) White enamel 500 parts Rutile Titanium Dioxide (Du Ponts R-6l0 orequal) with 300 parts of the epoxidized oil of Example XI and 10 partsof a silica product marketed as Cabosil by Cabot Company were mixed andground on a three roller mill in a conventional manner. To this grindingpaste was added 500 parts of the partial ester of Example IV and 100parts of the acetate of the mono ethyl ether of ethylene glycol(Cellosolve Acetate). This enamel was 78.7% solids and had a P.V.C. of20.4%. Cured films had a 60 gloss of 92% upon baking at 250 for 20minutes, or suitable air drying.

(B) Green enamel 5 parts of phthalocyanine green (Du Ponts RamapoGP-SOlD or equal), 100 parts titanium dioxide (Du Ponts R-510 or equal)and 85 parts of the epoxidized oil of Example XIII were mixed and groundas above. This paste was mixed with 115 parts of the partial ester ofExample IV and 24 parts of Cellosolve Acetate to give a green enamelwith a percent solids of 78.5% and a P.V.C. of 17.3%. Films made fromthis enamel may 8 be air dried or baked under standard conditions andwere very glossy, very, hard and resistant to chemicals.

(C) Yellow enamel A' yellow enamel with a P.V.C. 0f 14% was made bygrinding 30 parts Cadmium Yellow (Imperial Color X-23l5), 270 partstitanium dioxide (Du Ponts R-6l0), 4 parts Cabosil (Cabot Co.), 240parts of the epoxidized oil from Example XI and parts of the epoxidizedoil from Example XIII to form a mill paste as above. To this mill pastewas added 410 parts of the partial ester of Example IV and partsCellosolve Acetate to make the final enamel. The enamel when cast as athin film, air dried or conventionally'baked, gave a glossy, hardresistant coating.

(D) White enamel 500 parts Rutile Titanium Dioxide (Du Pont R-61O orequal), 15 parts of a silica product marketed as Cabosil M-S by CabotCompany, 40 parts of theacetate of the mono ethyl ether of ethyleneglycol and 330 parts of the partial ester described in Example IV weremixed and ground in a conventional manner on a three roller mill. Tothis grinding paste was added 222 parts of the epoxidized oil describedin Example XIII and 8 parts of the acetate of the mono-ethyl ether ofethylene glycol. This enamel was 78.7% solids and had a P.V.C. of 20.4%.Cured films had a 60 gloss of 92% after air drying or conventionalbaking as herein described.

Essentially these formulations provide for improved economics of solventusage, formulating versatility, ease of handling, and higher solidslevels without seed formation in applied films having improved colorretention, and other improved and beneficial properties.

To show by data, some improved properties of dried films using thepartial esters and epoxy materials of the above examples, the followingtables are given. Table I concerns air dry film properties of several ofthe many possible combinations and Table II concerns baked filmproperties of similar combinations.

TABLE I..AIR DRY FILMS Partial Wt. Wet Non- Tack 24 Hr. Example EsterEpoxy Partial Wt. Percent Film Trans. Free Sward N0. Ex.N0. Ex. No EsterEpoxy N.V. Thick., Time, Time, Hard.

Solids Mils Min. Min.

TABLE IL-BAKED FILMS Bake Partial Epoxy Wt. Wt. Percent Wet FilmSchedule Hot Sward Example N0. Ester Ex. No. Partial Epoxy N.V. Thick,mrn.at Hard Hard Ex. N0. Ester Mils 3% 30 F. XIII 30 24 3 250 Ex. 44XIII 30 30 3 250 Ex. 38 XIII 27 32.4 3 250 Ex. 35 24 33.5 g 250 5. 14 12250 x. 52 XIII 12 12 3 250 Ex. 52 X111 12 3 250 Ex. 43 XIII 24 24 3 250Ex. 54 XIII 24 24 3 250 Ex. 54 XIII 12 15 3 250 Ex. 35 5 ii 3 3 28 I 562 52 XIII 12 9 3 250 E; 52 XIII 12 12 3 250 Ex. 40 XIII 12 15 3 250 Ex.18 XI 12 9.5 3 250 Ex. 20 g 12 13 g 1 314. 55 12 25 x. 45 XII 12 12 3250 Ex. XII 12 15 3 250 Ex. 25 XIII 12 9 3 250 EX. 40 XIII 12 12 3 250Ex. 48 XIII 12 15 3 250 Ex. 45 III 12 12 3 250 Ex. 45 M11 12 6 75 3 250Ex. 25 XIv 5 g? 12{ g 75 3 250 vo. 30 12 g 75 3 250 vs. 12 1g 75 3 25045 54 12{ 6 75 3 250 25 gt? 12 g 75 3 250 32 12 g 75 3 250 35 XIII 12 1273 3 250 Ex. 45 12 1g 75 3 250 Ex. 12 g 75 3 250 v.o. 25 {ggn 12 g 75 3250 vo 32 12 6 75 3 250 V.G. 40

Listed in the columns in Table I from left to right are the examplenumbers; the example number of the partial ester or resinuouspolycarboxylic acid, the example number of the epoxidized material, theweight of partial ester, the weight of epoxidized material, the percentsolids of the partial acid-epoxidized material blend, the wet filmthickness in mils, the non-transfer time in minutes, the tack free timein minutes and the 24-hour Sward hardness.

The films were drawn down approximately 1 hour after the partial ester,epoxidized material and solvent were blended. In some exemplary casesmore than one epoxidized material was used with the partial esters.Catalysts were not found necessary to speed the cure of the preferredsystem. Some systems less preferred, but not specifically disclosed, mayrequire catalysts such as benzyl trimethyl ammonium hydroxide to speedthe cure. In other cases .005 to 2% phosphoric acid may serve as acuring catalyst.

Listed in Table II are the properties of partial esterepoxidizedmaterial films which were cured by baking at various schedules. Thecolumns in Table II represent from left to right the example number, theexample number of partial ester used, the example number of epoxidizedmaterial used, the weight of partial ester, the weight of epoxidizedmaterial, the percent solids of blend, the wet film thickness, thecuring schedule and the Sward hardness of the cured films.

The epoxidized fatty esters and partial ester blends, as hereindescribed, have a room temperature pot life varying from a few hours toseveral days depending upon the epoxidized fatty ester material, thepartial ester and the percent solids of the blend. In general, the potlife is shortened by increasing the oxirane content of the epoxidizedester material, by increasing the reactivity of the partial ester or byincreasing the percent solids in the blend of the partial esters andepoxidized ester material. In addition, the blends which containchlorine groups appear the most reactive in normal air temperature curewhile at baking temperatures above F. the presence of chlorine is notrequired for satisfactorily curing epoxidized fatty oils.

From the above, it will be apparent that the essential discovery lies ina manner of successfully utilizing the more economical polycarboxylicanhydrides in applying normally non-drying epoxy fatty ester compoundsas clear or pigmented coating vehicles. However, some variations andmodifications of this improvement in forming hard, durable, flexiblefilms utilizing the non-drying epoxidized fatty esters by combinationwith the described resinous partial esters of condensationesterification polymers, may be made Without departing from the spiritand scope of the embodiment, given by way of the examples and expressedby the terms of the appended claims.

We claim:

1. A two-package coating system capable of forming a hard coating, saidcoating system consisting essentially of:

(a) in a first package, curable epoxidized fatty compound selected fromthe group consisting of epoxidized fatty oils, epoxidized monohydricalcohol esters of fatty acids, epoxidized polyhydric alcohol esters offatty acids, epoxidized fatty nitriles, epoxidized fatty amides,epoxidized fatty amines, and epoxidized fatty alcohol-s; said fattycompound having 8-26 carbon atoms in the fatty radicals and an internaloxirane value of from 3% to 10%, and

(b) in a second package, polyester curing agent for said epoxidizedfatty compound; said polyester curin g-agent having an acid value of atleast 50; said polyester curing agent being esterification reactionproduct of polyhydric alcohol and polycarboxylic '1 1 acid wherein theesterification reaction mixture has an initial ratio of carboxyl tohydroxyl of 1-3 to 1; said reaction product comprising polyester of theformula:

wherein n is at least two, wherein R is polyhydric alcohol residue, andwherein R is polycarboxylic acid residue.

2. A coating system of the type described in claim 1 wherein saidcurable epoxidized fatty compound in said first package is monomericepoxidized ester of fatty acid, said ester having 12 to 22 carbon atomswith internal oxirane in each fatty radical and 1 to carbon atoms in thealcohol radical, the oxirane value of said ester being at least 6%.

3. A coating system of the type described in claim 2 wherein from 50-150parts of polyester curing agent are present per 100 parts of epoxidizedfatty ester and wherein said polycarboxylic acid comprises chlorinatedpolycarboxylic acid.

4. Substrate coated with the cured filmobtained by mixing and drying thecoating system defined in claim 2.

5. A two-package coating system capable of forming a hard coating, saidcoating system consisting essentially of:

(a) in a first package, solvent and curable monomeric epoxidized esterof fatty acid; said ester having 12 to 22 carbon atoms with internaloxirane in each fatty radical and 1 to 10 carbon atoms in the alcoholradical, the oxirane value of said ester being from 6% to 10%, and

(b) in a second package, solvent and polyester curing agent for saidepoxidized ester; said polyester curing agent having an acid value ofatleast 50; said polyester curing agent being esterification reactionproduct of polyhydric alcohol and polycarboxylic acid wherein thees-terification reaction mixture has an initial ratio of carboxyl tohydroxyl of about 1.8 to 1 and wherein said polycarboxylic acidcomprises chlorinated polycarboxylic acid; said reaction productcomprising polyester of the formula:

wherein n is at least two, wherein R is polyhydric alcohol residue, andwherein R is polycarboxylic acid residue, (c) from 50-150 parts ofpolyester curing agent being present per 100 parts of epoxidized fattyester. 6. A two-package coating system capable of air drying, saidsystem comprising first and second packages:

(a) in a first package, curable epoxidized fatty ester having 8 to 26carbon atoms in the fatty radicals and an internal oxirane value of from3% to 10%, and (b) in a second package, polyester curing agent for saidepoxidized fatty ester; said curing agent having an acid value of atleast 50; said curing agent being reaction product of polyhydric alcoholand polycarboxylic acid, said reaction product comprising polyester ofthe formula:

wherein n is at least two, wherein R is polyhydric alcohol residue and Ris polycarboxylic acid residue;

said curing agent being prepared from an esterification reaction mixturehaving an initial ratio of car,-

boxyl to hydroxyl of from 13 to 1; said reaction mixture containinghexachloroendomethylene tetrahydrophthalic acid.

7. A coating system of the type described in claim 6 wherein from 50 to150 parts of curing agent are present per parts of epoxidized fattyester and wherein said fatty ester is fatty glycerol ester having aninternal oxirane value of at least 6%.

8. A coating system of the type described in claim 7 wherein saidpolyhydric alcohol comprises pentaerythritol.

9. A coating system of the type described in claim 8 wherein saidpolycarboxylic acid is a mixture of phthalic anhydride andhexachloroendomethylene tetrahydrophthalic acid and wherein said curingagent has an acid value of at least about 160. v

10. Substrate coated with the cured film obtained by mixing and dryingthe coating system defined in claim 6.

11. A two-package coating system capable of air drying to form a hard,mar-resistant, durable coating, said coating system consistingessentially of first and second packages:

(a) in a first package, curable epoxidized ester of C C fatty acid, saidcurable epoxidized ester having an internal oxirane value of 3% to 10%,and

(b) in a second package, polyester curing agent for said epoxidizedester; said polyester curing agent having an acid value of at least 50;said polyester curing agent being esterification reaction product ofpentaerythritol, phthalic anhydride and hexachloroendomethylenetetrahydrophthalic acid wherein the esterification reaction mixture hasan initial ratio of carboxyl to hydroxyl of l3 to 1; said esterificationreaction product comprising, as the predominant species, polyester ofthe formula:

wherein n is at least two, wherein R is polyhydric alcohol residue, andwherein R is polycarboxylic acid residue.

12. A coating system of the type defined in claim 11 wherein saidinitial ratio of carboxyl to hydroxyl is about 1.8 to 1 and wherein saidfirst and second packages each contain solvent.

13. Substrate coated with the cured film obtained by mixing and dryingthe two-package coating system defined in claim 11, from 50-150 parts ofsaid polyester curing agent being present per 100 parts of epoxidizedester.

14. A two-package coating system capable of drying to form a hard,mar-resistant, durable coating, said coating composition consistingessentially of first and second packages:

(a) in a first package, curable epoxidized fatty compound selected fromthe group consisting of epoxidized fatty oils, epoxidized monohydricalcohol esters of fatty acids, epoxidized polyhydric alcohol esters offatty acids, epoxidized fatty nitriles, and epoxidized fatty alcohols,said fatty compounds having 8 to 26 carbon atoms in the fatty radicalsand an internal oxirane value of 6% to 10%, and

(b) in a second package, polyester curing agent for said epoxidizedfatty compounds; said curing agent having an acid value greater than 50;said polyester curing agent being the esterification reaction product ofpolyhydric alcohol selected from the group consisting of ethyleneglycol, propylene glycol, glycerol, trimethylolethane,trimethylolpropane, sorbitol, pentaerythritol, dipentaerythritol, andtripentaerythritol, and at least one polycarboxylic acid selected fromthe group consisting of phthalic acid, phthalic anhydride,tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalicacid, hexahydrophthalie anhydride, hexachloroendomethylenetetrahydrophthalic anhydride, hexachloroendomethylene tetrahydrophthalicacid, maleic acid, maleic anhydride, trimellitic acid, trimelliticanhydride, tetrachlorophthalic acid, tetrachlorophthalic anhydride,monochloro- 13 phthalic acid, monochlorophthalic anhydride,hexachlorophthalic acid and hexachlorophthalic anhydride, saidesterification reaction product containing as the predominant species,polyester of the formula:

wherein n is at least two, wherein R is polycarboxylic acid residue andR is polyhydric alcohol residue, and wherein the esterification reactionmixture has an initial ratio of carboxyl to hydroxyl of 1-3 to 1.

15. A coating system of the type described in claim 14 wherein at leasta portion of the polycarboxylic acid is hexachloroendomethylenetetrahydrophthalic acid and wherein said coating system is capable ofair drying.

16. Polyester having an acid value of at least 50, said polyester beingthe esterification reaction product of polyhydric alcohol andpolycarboxylic acid wherein the esterification reaction mixture has aninitial ratio of carboxyl to hydroxyl of 1-3 to 1; said reaction productcontaining, as the predominant species, polyester of the formula:

wherein n is at least two, wherein R is polyhydric alcohol residue andwherein R is polycarboxylic acid residue, said polycarboxylic acidcomprising chlorinated polycarboxylic acid.

17. Polyester of the type described in claim 16 wherein saidpolycarboxylic acid comprises hexachloroendomethylene-tetrahydrophthalicacid.

18. Polyester of the type described in claim 16 wherein said reactionmixture is a mixture of pentaerythritol, phthalic anhydride andhexachloroendomethylene tetrahydrophthalic acid and the initial ratio ofcarboxyl to hydroxyl is about 1.8 to 1.

References Cited by the Examiner UNITED STATES PATENTS 2,720,500 10/1955Cody 26022 2,912,409 11/ 1959 Nischk et al. 260 2,959,559 11/1960 Delius26075 3,027,357 3/1962 Stickle 26078.3 3,031,434 4/1962 Radlove 26078.43,043,717 7/1962 Budde 26022 3,050,480 8/1962 Budde 26022 3,086,949 4/1963 Chatfield 26022 3,098,052 7/1963 Schmitz et a1. 26022 FOREIGNPATENTS 569,634 1/1959 Canada. 806,730 12/ 1958 Great Britain.

LEON I. BERCOVITZ, Primary Examiner.

MILTON STERMAN, JAMES A. SEIDLECK,

Examiners.

1. A TWO-PACKAGE COATING SYSTEM CAPABLE OF FROMING A HARD COATING, SAID COATING SYSTEM CONSISTING ESSENTIALLY OF: (A) IN A FIRST PACKAGE, CURABLE EPOXIDIZED FATTY COMPOUND SELECTED FROM THE GROUP CONSISTING OF EPOXIDIZED FATTY OILS, EPOXIDIZED MONOHYDRIC ALCOHOL ESTERS OF FATTY ACIDS, EPOXIDIZED POLYHYDRIC ALCOHOL ESTERS OF FATTY ACIDS, EPOXIDIZED FATTY NITRILES, EPOXIDIZED FATATY AMIDES, EPOXIDIZED FATTY AMINES, AND EPOXIDIZED FATTY ALCOHOLS; SAID FATTY COMPOUND HAVING 8-26 CARBON ATOMS IN THE FATTY RADICALS AND AN INTERNAL OXIRANE VALUE OF FROM 3% TO 10%, AND (B) IN A SECOND PACKAGE, POLYESTER CURIG AGENT FOR SAID EPOXIDIZED FATTY COMPOUND; SAID POLYESTER CURIN GAGENT HAVING AN ACID VALUE OF AT LEAST 50; SAID POLYESTER CURING AGENT BEING ESTERIFICATION REACTION PRODUCT OF POLYHYDRIC ALCOHOL AND POLYCARBOXYLIC ACID WHEREIN THE ESTERIFICATION REACTION MIXTURE HAS AN INITIAL RATION OF CARBOXYL TO HYDROZXYL OF 1-3 TO 1; SAID REACTION PRODUCT COMPRISING POLYESTER OF THE FORMULA: 